1. Field of the Invention
The present invention relates to a buckle of an inserting type comprising female and male members, i.e., a buckle body and an insertion body. More particularly, it relates to a buckle for fastening a belt generally used for clothes, shoes, helmets, baby cars or sporting goods.
2. Description of the Related Art
A conventional buckle of this type comprising a buckle body and insertion body is formed into a flat cylindrical body as shown in FIG. 14, which is disclosed in U.S. Pat. No. 5,309,610. The buckle comprises the buckle body 1' having at its opposite side surfaces opening portions 8', and the insertion body 2' having at its one end a belt-mounting part having a belt-folding portion 22' and a belt-fastening portion 21' and a pair of flexible operating portions 25' projecting from opposite sides of the insertion body 2' extending from the belt-mounting part toward the other end. Each of the operating portions 25' has at its outer side surface an engaging portion 28' to be engaged with the opening portion 8' of the buckle body 1'. An upper plate 3' of the buckle body 1' is extended to provide an extending portion 30'. When the buckle body 1' and the insertion body 2' are engaged with each other, the belt B' is caught on the belt-folding portion 22', and then the extending portion 30' of the upper plate 3' of the buckle body 1' is brought into contact with an upper surface of the folded belt B' under pressure so as to prevent the belt B' from being loosened.
Further, Japanese Patent Laid-open No. 9-135709 discloses a buckle as shown in FIG. 15. This buckle comprises a buckle body 1" formed into a flat cylindrical shape and having at its opposite side surfaces opening portions 8", and an insertion body 2" having a belt-fastening portion 21", a belt-folding portion 22" with a step 22a" at its inner side, a base portion 23" on a further inner side thereof. The insertion body 2' further has a resilient projection 40" urged toward the step 22a" of the belt-folding portion 22", and a pair of operating portions 25" projecting from the base portion 23". Each of the operating portion 25" has at its outer side surface an engaging portion 28". The resilient projection 40" is urged toward the step 22aw and brought into resilient contact with the belt which is caught on the belt-folding portion 22" and folded, thereby fastening the belt under pressure so as to prevent the belt from being loosened.
In the case of the above-described buckle shown in FIG. 14, when the buckle body 1' and the insertion body 2' are engaged with each other, since the engaging state of the belt B' between the belt-folding portion 22' and the belt-fastening portion 21' can not be checked visually, it is not possible to smoothly adjust the length of the belt B' at the time of engagement of the buckle. Further, since the upper plate 3' of the buckle body 1' completely covers the belt-folding portion 22' and the belt-fastening portion 21' of the insertion body 2', and presses the belt B' caught on the belt-folding portion 22', the length of the belt can not be adjusted at the time of engagement.
In the case of the buckle shown in FIG. 15, when the buckle body 1" and the insertion body 2" are in engagement or out of engagement with each other, the resilient projection 40" must be inclined so as to be separated from the belt-folding portion 22" when the length of the belt is adjusted. Therefore, the adjusting operation is troublesome. Further, when the belt is mounted to the insertion body 2", since the resilient projection 40" must be always operated, the inserting operation of the belt is also troublesome. Furthermore, there is a problem that it is difficult to integrally mold the buckle because of the belt-folding portion 22" and the resilient projection 40" of the insertion body 2".